Evaluation of Tranexamic Acid in Bleeding Control in Primary Total Knee Arthroplasty

Total knee arthroplasty (TKA) has been more prevalent due
to the increase in life expectancy and is already one of the most
common elective procedures performed in the United States...


Introduction
Total knee arthroplasty (TKA) has been more prevalent due to the increase in life expectancy and is already one of the most common elective procedures performed in the United States.
Considering TKA to be a major surgery and predicting blood loss, the need for blood transfusion becomes a reality in some settings.
Both allogeneic transfusion and blood loss can potentially result in substantial increases in costs and significant complications such as postoperative infection, delayed physical recovery, increased hospital stay and increased mortality [1]. Peroperative blood loss can vary from 300ml to 2000ml in primary TKA procedures [2,3]. These complications may be more evident in patients with pre-existing medical comorbidities, including degree of deformity, heart, lung, kidney disease and surgical time [4,5].
Although there is a very large number of rigorous tests, blood transfusion causes significant inherent risks including hemolytic reactions, inflammatory tissue damage, infection, among other blood-borne diseases, as well as the immune modulation caused by allogeneic transfusion, contamination and immunological reactions [6,7]. In view of the higher financial cost and these possible complications and adverse events associated with blood loss and blood transfusion, it is necessary to investigate and discover strategies to reduce bleeding in TKA. ATX is an antifibrinolytic, inhibits the dissolution of clots by blocking the formation of plasma by not activating the coagulation cascade, reducing the intensity and risks of bleeding [8][9][10]. The objective of this study was to evaluate the influence of ATX in reducing bleeding in primary knee total arthroplasty surgeries and to evaluate the decrease in the need for blood transfusion.

Methods
It is a prospective cohort where 40 patients were evaluated, from December 2018 to December 2019, with gonartrosetri compartmental. The work was approved by the Research Ethics Committee of the Center for Biological and Health Sciences at the Federal University of the State of Rio de Janeiro (UNIRIO). CAAE 80969517.0.0000.5258. Inclusion criteria were idiopathic gonarthrosis, age between 53 to 65 years, aligned lower limb axis and body mass index less than 35 kg / m 2 and joint stability.
The exclusion criteria were non-idiopathic gonarthrosis, age less than 53 years and more than 65, deformity of the lower limb and body mass index greater than 35kg /m 2 and joint instability. To

Results
The variables investigated in this study were: surgery side, age, number of dirty compresses, weight of dirty compresses (in grams), preoperative collector (in ml), blood in the compress (in ml), preoperative bleeding (in ml) , postoperative bleeding (in ml) and total bleeding (in ml).

Exploratory Analysis (Tables 1-3)
Based on the data above, the distributions of the variables were similar. Viewing this same data in the form of boxplots, in Figure   1, both sides had a similar distribution of bleeding, generating an indication that there is no difference in bleeding between the operated sides excluding the use of the medicine (Figure 1). We observed that the test group on both sides operated on had less bleeding than the control group ( Figure 2).     For the age analysis, we created the Age Range variable from the median age. We obtained a median of 59 and two new options for a new variable created: "Age group from 59 years old" and "Age group below 59 years". Analogously to the analysis of the operated sides, we observed that the Age Group variable has differences in distributions between the Age Group classes (Table 4) and ( Figure   3). The older group had greater total bleeding than the younger group ( Figure 3 & Table 5).   We found that again the groups in which the drug was tested were those that obtained lower medians compared to their peers in the Control Group (Figure 4). Evaluating only the differences in the total bleeding variable between treatments, that is, between the Control group and the Test group, the Test group had a lower amount of total bleeding when compared to the Control group. Table 6 shows the summary measures of these two groups ( Table 6). The Figure 5 representing the measures in Table 6.    In the Test group only one patient who had 1491ml Total Bleeding needed a blood bag.

Conclusion
We concluded that intravenous ATX applied at a dose of 20mg / kg after anesthetic induction was effective in satisfactorily reducing blood losses resulting from TKA surgery, which consequently resulted in a reduction in the need for blood transfusion.